[TowerTalk] Lightning protection - length of grounding rodsruns from tower?

[Larry]

The Polyphaser book recommended ground rods spaced at 2x the length of the 
ground rods. The purpose was to spread the charge out in the event of a hit. 
So is that theory or explanation now out, disproved, or ...?

It has been a long time since I looked at the book so I may not have 
remembered it correctly.

73, Larry  W6NWS

-----Original Message----- 
From: Mike Reublin NF4L
Sent: Thursday, January 29, 2015 7:42 AM
To: Ray Benny
Cc: towertalk reflector
Subject: Re: [TowerTalk] Lightning protection - length of grounding rodsruns 
from tower?

My electrician (who is regarded as a grounding expert here) told me the 
extra ground rods would add absolutely nothing to the protection provided by 
the Ufer ground of the base. OTOH having the rods wouldn't hurt anything. 
Since he'd charge me to drive 'em I decided to forego them. He megged the 
tower at 4 ohms. Water level is about 3 feet.
73
Mike NF4L

> On Jan 28, 2015, at 7:37 PM, Ray Benny <rayn6vr at cableone.net> wrote:
>
> I am about to start the grounding system for my 90ft free standing tower. 
> I
> do have the Ufer ground / rebars connected to the tower. The next part is
> to run 'spokes' of ground rods out a distance from the base of the tower.
> Ground rods are connected with #4 copper wire with Cadwell thermal 
> devices,
>
> My question, or request for your thoughts, is it better to run 3 grounding
> wires out 40, 50 or 60 ft (8 ft ground rods about every 16 ft connected
> with bare #4 wire) or to run say 6 ground wires out, perhaps 30 - 40 ft
> outwards? I have room in all but one direction to trench out a 100 ft if
> that would be even better yet.
>
> I'm in the Arizona high desert, at 5000 ft. My soil is hard packed dirt 
> and
> conductivity is very low, with no moisture at all, except during our 
> winter
> storms and summer monsoons. Its takes about 5 minutes to drive an 8 ft
> ground rod with an electric impact driver. Water level is about 350 ft.
>
> Your thoughts and knowledge please.
>
> Tnx,
>
> Ray,
> N6VR
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